Reducing Irrigation Deficiencies Based Optimizing Model for Multi-Reservoir Systems Utilizing Spider Monkey Algorithm

Continuous droughts and water scarcity have led to the need for optimal exploitation of dams’ reservoirs. Thus, the new meta-heuristic algorithm, spider monkey, is suggested for complex modeling of the multi-reservoir system in Iran with the aim of decreasing irrigation deficiencies. Golestan and Voshmgir dams’ operations are optimized with the spider monkey algorithm. The algorithm based on the exchange of information between local and global leaders with the other monkeys which improves the convergence speed. Average deficiencies for Golestan dam is computed as 2.1 and 1.9 MCM by spider monkey algorithm while it is respectively computed as 6.7, 16.4, 11.1, 4.1, 14.6, 19 MCM by particle swarm algorithm, harmony search algorithm, imperialist competitive algorithm, water cycle algorithm, genetic algorithm, and standards operation policy method. Also, the computation time of the spider monkey algorithm is 50 and 47 s for the Golestan and Voshmgir dams while the genetic algorithm optimizes the problem in 172.6 s and 112 s and the particle swarm algorithm needs 117.4 s and 100 s for the Golestan and Voshmgir, respectively. Also, root means square error (RMSE) and mean absolute error between demand and released water for the spider monkey algorithm have the least values among the applied evolutionary algorithms. Thus, the spider monkey algorithm is suggested as an appropriate method for optimizing the operation policy for the dam and reservoir systems.     

Multi-objective optimization of molten carbonate fuel cell system for reducing CO2 emission from exhaust gases

The aim of this paper is to investigate the implementation of a molten carbonate fuel cell (MCFC) as a CO₂ separator. By applying multi-objective optimization (MOO) using the genetic algorithm, the optimal values of operating load and the corresponding values of objective functions are obtained. Objective functions are minimization of the cost of electricity (COE) and minimization of CO₂ emission rate. CO₂ tax that is accounted as the pollution-related cost, transforming the environmental objective to the cost function. The results show that the MCFC stack which is fed by the syngas and gas turbine exhaust, not only reduces CO₂ emission rate, but also produces electricity and reduces environmental cost of the system.     

Coherent differential absorption lidar measurements of CO2

A differential absorption lidar has been built to measure CO2 concentration in the atmosphere. The transmitter is a pulsed single-frequency Ho:Tm:YLF laser at a 2.05-microm wavelength. A coherent heterodyne receiver was used to achieve sensitive detection, with the additional capability for wind profiling by a Doppler technique. Signal processing includes an algorithm for power measurement of a heterodyne signal. Results show a precision of the CO2 concentration measurement of 1%-2% 1sigma standard deviation over column lengths ranging from 1.2 to 2.8 km by an average of 1000 pulse pairs. A preliminary assessment of instrument sensitivity was made with an 8-h-long measurement set, along with correlative measurements with an in situ sensor, to determine that a CO2 trend could be detected.     

Numerical simulation and experimental validation of a ductile damage model for DIN 1623 St14 steel

St14 steel (DIN 1623) is widely used in sheet metal forming industries because of its remarkable formability and also its low price. In this paper, damage behaviour of St14 steel is studied in order to be used in complex forming conditions with the goal of reducing the number of costly trials. Damage parameters of St14 steel have been determined by using standard tensile and Vickers micro-hardness tests. A fully coupled elastic-plastic-damage model has been developed and implemented into an explicit code. With this model, damage propagation and crack initiation, and ductile fracture behaviour of drilled and notched specimens are predicted. The model can quickly predict both deformation and damage behaviour of the part because of using plane stress algorithm, which is valid for thin sheet metals. Experiments are also carried out to validate the results. It is concluded that finite element analysis (FEA) in conjunction with continuum damage mechanics (CDM) can be used as a reliable tool to predict ductile damage and fracture of St14 steel.     

Conjugated linoleic acid‐producing enzymes: A bioinformatics study

Linoleic acid isomerases (LAI) are enzymes responsible for conversion of linoleic acid (LA) to conjugated linoleic acids (CLA) in different isomeric forms. CLAs are well known for numerous beneficial effects as functional foods. Despite identification of several LAI producing‐bacteria and release of their LAI nucleotide sequences to Bio‐Banks, no related bioinformatics study on these important enzymes is addressed yet. To gain insights into the structural/functional and phylogentic relations of LAIs as well as recombinant production of the desired enzyme, we employed several bioinformatical tools to analyze their primary structure and physicochemical properties. The results indicated that LAIs produced in different bacterial strains might be divided in two distinct families (Propionibacterium acnes and myosin cross‐reactive antigen (MCRA)‐like LAIs) with specific isomerase activities. In another part of the study, physicochemical properties, solubility upon over expression in E. coli, disulfide bond formation, and potential glycosylation sites in LAI sequences were predicted using bioinformatics tools and the most appropriate strategy for recombinant production of each LAI was determined. Our predicted data may be useful for further experimental studies toward production of the desired LAI.     

Investigation of 304L stainless steel in a NaCl solution using a microcapillary electrochemical droplet cell: Comparison with conventional electrochemical techniques

In this work a comparison has been made between a localized (micro scale) and a conventional (large-scale) corrosion study of 304L stainless steel in a sodium chloride solution using Tafel plots and electrochemical impedance spectra. Results show the high ability of microelectrochemical techniques for the local investigation of corrosion procedures on solid surfaces, something which is not feasible with conventional large-scale techniques. In the second experiment the microelectrochemical behavior of a faulty copper layer on 304L stainless steel was investigated using linear sweep voltammetry. Glass capillaries touching only small areas of the surface were used and the copper coated surface of the steel sample was scanned in a 9 by 6 matrix (54 measurements) while acquiring data. The obtained corrosion potentials for both defect and intact areas were used to map the surface. The surface plot shows the exact position of the defect point in the coating layer.     

Pulse shaping fiber laser at 1.5 μm

In this paper we present, for the first time to our knowledge, a new pulse shaping technology (modulation schemes for seed laser) used to mitigate pulse narrowing effect and SBS effect in a high energy Er:Yb codoped fiber master oscillator power amplifier system at 1.5 μm to obtain longer pulse duration and higher energy. An average power of over 1.3 W and a pulse energy of over 0.13 mJ were obtained at 10 kHz repetition rate with a pulse duration of 200 ns and near-diffraction-limited beam quality (M(2)<1.2).     

Numerical and experimental investigation of inward tube electromagnetic forming

In this work, experimental and numerical simulation of high-speed inward forming of tubes on a die in electromagnetic forming (EMF) system using a compression coil is presented. A 2D axi-symmetric electromagnetic model is used to calculate magnetic field and magnetic forces. Modified loose-coupled simulations of electromagnetic and structural aspects of EMF process are reported and emphasized in this paper. During the simulation, in each time step, the transient magnetic forces are obtained from the electromagnetic model and used as input load to the mechanical model. Based on the calculated deformation, in each step, the tube geometry in the electromagnetic model is updated to calculate the electromagnetic forces in proceeding step. Tube material, AA 6061-T6, is assumed to obey the Johnson-Cook (J-C) rate-dependent model. Displacement and thickness variations of workpieces along the tube length are presented and discussed experimentally and numerically. The results demonstrate that various workpiece zones could be thickened or thinned based on various process parameters. In addition, it is seen that the increase of discharge voltage decreases the thickness at die radius and reverses the thickening trend at tip of the bead.